void main() {
 // Numbers
 int age = 25;
 double height = 5.9;

 // Strings
 String name = "Alice";

 // Booleans
 bool isStudent = true;

 // Lists
 List<int> numbers = [1, 2, 3, 4, 5];

 // Maps
 Map<String, int> ages = {'Alice': 25, 'Bob': 30};

 // Runs
 Runes input = Runes('\u{1f600}');
 String emoji = new String.fromCharCodes(input);

 // Symbols
 Symbol symbol = #mySymbol;

 // Dynamic
 dynamic variable = 123;
 variable = "Hello";

 // Void
 void sayHello() {
  print('Hello');
 }

 // Null
 int? nullableInt; // 默认为 null

 // Never
 Never throwException(String message) {
  throw Exception(message);
 }

 // Objects
 Object obj = "Hello";

 // Print all values
 print("Age: $age");
 print("Height: $height");
 print("Name: $name");
 print("Is Student: $isStudent");
 print("Numbers: $numbers");
 print("Ages: $ages");
 print("Emoji: $emoji");
 print("Symbol: $symbol");
 print("Variable: $variable");
 sayHello();
 print("Nullable Int: $nullableInt");
 try {
  throwException("This is an exception");
 } catch (e) {
  print(e.toString());
 }
 print("Object: $obj");
}



